greybus: es2: add ES2 Greybus Host driver

This is just a copy of ES1 for now, things will start to diverge soon.
Any common functionality will be factored out over time.

Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
This commit is contained in:
Greg Kroah-Hartman 2015-01-21 10:24:15 +08:00
parent 2ec515bfff
commit f587027e79
2 changed files with 619 additions and 0 deletions

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@ -22,6 +22,7 @@ obj-m += gb-phy.o
obj-m += gb-vibrator.o
obj-m += gb-battery.o
obj-m += gb-es1.o
obj-m += gb-es2.o
KERNELVER ?= $(shell uname -r)
KERNELDIR ?= /lib/modules/$(KERNELVER)/build

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@ -0,0 +1,618 @@
/*
* Greybus "AP" USB driver for "ES2" controller chips
*
* Copyright 2014 Google Inc.
* Copyright 2014 Linaro Ltd.
*
* Released under the GPLv2 only.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/sizes.h>
#include <linux/usb.h>
#include "greybus.h"
#include "svc_msg.h"
#include "kernel_ver.h"
/*
* Macros for making pointers explicitly opaque, such that the result
* isn't valid but also can't be mistaken for an ERR_PTR() value.
*/
#define conceal_urb(urb) ((void *)((uintptr_t)(urb) ^ 0xbad))
#define reveal_urb(cookie) ((void *)((uintptr_t)(cookie) ^ 0xbad))
/* Memory sizes for the buffers sent to/from the ES1 controller */
#define ES1_SVC_MSG_SIZE (sizeof(struct svc_msg) + SZ_64K)
#define ES1_GBUF_MSG_SIZE_MAX PAGE_SIZE
static const struct usb_device_id id_table[] = {
/* Made up numbers for the SVC USB Bridge in ES1 */
{ USB_DEVICE(0xffff, 0x0001) },
{ },
};
MODULE_DEVICE_TABLE(usb, id_table);
/*
* Number of CPort IN urbs in flight at any point in time.
* Adjust if we are having stalls in the USB buffer due to not enough urbs in
* flight.
*/
#define NUM_CPORT_IN_URB 4
/* Number of CPort OUT urbs in flight at any point in time.
* Adjust if we get messages saying we are out of urbs in the system log.
*/
#define NUM_CPORT_OUT_URB 8
/**
* es1_ap_dev - ES1 USB Bridge to AP structure
* @usb_dev: pointer to the USB device we are.
* @usb_intf: pointer to the USB interface we are bound to.
* @hd: pointer to our greybus_host_device structure
* @control_endpoint: endpoint to send data to SVC
* @svc_endpoint: endpoint for SVC data in
* @cport_in_endpoint: bulk in endpoint for CPort data
* @cport-out_endpoint: bulk out endpoint for CPort data
* @svc_buffer: buffer for SVC messages coming in on @svc_endpoint
* @svc_urb: urb for SVC messages coming in on @svc_endpoint
* @cport_in_urb: array of urbs for the CPort in messages
* @cport_in_buffer: array of buffers for the @cport_in_urb urbs
* @cport_out_urb: array of urbs for the CPort out messages
* @cport_out_urb_busy: array of flags to see if the @cport_out_urb is busy or
* not.
* @cport_out_urb_lock: locks the @cport_out_urb_busy "list"
*/
struct es1_ap_dev {
struct usb_device *usb_dev;
struct usb_interface *usb_intf;
struct greybus_host_device *hd;
__u8 control_endpoint;
__u8 svc_endpoint;
__u8 cport_in_endpoint;
__u8 cport_out_endpoint;
u8 *svc_buffer;
struct urb *svc_urb;
struct urb *cport_in_urb[NUM_CPORT_IN_URB];
u8 *cport_in_buffer[NUM_CPORT_IN_URB];
struct urb *cport_out_urb[NUM_CPORT_OUT_URB];
bool cport_out_urb_busy[NUM_CPORT_OUT_URB];
spinlock_t cport_out_urb_lock;
};
static inline struct es1_ap_dev *hd_to_es1(struct greybus_host_device *hd)
{
return (struct es1_ap_dev *)&hd->hd_priv;
}
static void cport_out_callback(struct urb *urb);
/*
* Buffer constraints for the host driver.
*
* A "buffer" is used to hold data to be transferred for Greybus by
* the host driver. A buffer is represented by a "buffer pointer",
* which defines a region of memory used by the host driver for
* transferring the data. When Greybus allocates a buffer, it must
* do so subject to the constraints associated with the host driver.
* These constraints are specified by two parameters: the
* headroom; and the maximum buffer size.
*
* +------------------+
* | Host driver | \
* | reserved area | }- headroom
* | . . . | /
* buffer pointer ---> +------------------+
* | Buffer space for | \
* | transferred data | }- buffer size
* | . . . | / (limited to size_max)
* +------------------+
*
* headroom: Every buffer must have at least this much space
* *before* the buffer pointer, reserved for use by the
* host driver. I.e., ((char *)buffer - headroom) must
* point to valid memory, usable only by the host driver.
* size_max: The maximum size of a buffer (not including the
* headroom) must not exceed this.
*/
static void hd_buffer_constraints(struct greybus_host_device *hd)
{
/*
* Only one byte is required, but this produces a result
* that's better aligned for the user.
*/
hd->buffer_headroom = sizeof(u32); /* For cport id */
hd->buffer_size_max = ES1_GBUF_MSG_SIZE_MAX;
BUILD_BUG_ON(hd->buffer_headroom > GB_BUFFER_HEADROOM_MAX);
}
#define ES1_TIMEOUT 500 /* 500 ms for the SVC to do something */
static int submit_svc(struct svc_msg *svc_msg, struct greybus_host_device *hd)
{
struct es1_ap_dev *es1 = hd_to_es1(hd);
int retval;
/* SVC messages go down our control pipe */
retval = usb_control_msg(es1->usb_dev,
usb_sndctrlpipe(es1->usb_dev,
es1->control_endpoint),
0x01, /* vendor request AP message */
USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
0x00, 0x00,
(char *)svc_msg,
sizeof(*svc_msg),
ES1_TIMEOUT);
if (retval != sizeof(*svc_msg))
return retval;
return 0;
}
static struct urb *next_free_urb(struct es1_ap_dev *es1, gfp_t gfp_mask)
{
struct urb *urb = NULL;
unsigned long flags;
int i;
spin_lock_irqsave(&es1->cport_out_urb_lock, flags);
/* Look in our pool of allocated urbs first, as that's the "fastest" */
for (i = 0; i < NUM_CPORT_OUT_URB; ++i) {
if (es1->cport_out_urb_busy[i] == false) {
es1->cport_out_urb_busy[i] = true;
urb = es1->cport_out_urb[i];
break;
}
}
spin_unlock_irqrestore(&es1->cport_out_urb_lock, flags);
if (urb)
return urb;
/*
* Crap, pool is empty, complain to the syslog and go allocate one
* dynamically as we have to succeed.
*/
dev_err(&es1->usb_dev->dev,
"No free CPort OUT urbs, having to dynamically allocate one!\n");
return usb_alloc_urb(0, gfp_mask);
}
static void free_urb(struct es1_ap_dev *es1, struct urb *urb)
{
unsigned long flags;
int i;
/*
* See if this was an urb in our pool, if so mark it "free", otherwise
* we need to free it ourselves.
*/
spin_lock_irqsave(&es1->cport_out_urb_lock, flags);
for (i = 0; i < NUM_CPORT_OUT_URB; ++i) {
if (urb == es1->cport_out_urb[i]) {
es1->cport_out_urb_busy[i] = false;
urb = NULL;
break;
}
}
spin_unlock_irqrestore(&es1->cport_out_urb_lock, flags);
/* If urb is not NULL, then we need to free this urb */
usb_free_urb(urb);
}
/*
* Returns an opaque cookie value if successful, or a pointer coded
* error otherwise. If the caller wishes to cancel the in-flight
* buffer, it must supply the returned cookie to the cancel routine.
*/
static void *buffer_send(struct greybus_host_device *hd, u16 cport_id,
void *buffer, size_t buffer_size, gfp_t gfp_mask)
{
struct es1_ap_dev *es1 = hd_to_es1(hd);
struct usb_device *udev = es1->usb_dev;
u8 *transfer_buffer = buffer;
int transfer_buffer_size;
int retval;
struct urb *urb;
if (!buffer) {
pr_err("null buffer supplied to send\n");
return ERR_PTR(-EINVAL);
}
if (buffer_size > (size_t)INT_MAX) {
pr_err("bad buffer size (%zu) supplied to send\n", buffer_size);
return ERR_PTR(-EINVAL);
}
transfer_buffer--;
transfer_buffer_size = buffer_size + 1;
/*
* The data actually transferred will include an indication
* of where the data should be sent. Do one last check of
* the target CPort id before filling it in.
*/
if (cport_id == CPORT_ID_BAD) {
pr_err("request to send inbound data buffer\n");
return ERR_PTR(-EINVAL);
}
if (cport_id > (u16)U8_MAX) {
pr_err("cport_id (%hd) is out of range for ES1\n", cport_id);
return ERR_PTR(-EINVAL);
}
/* OK, the destination is fine; record it in the transfer buffer */
*transfer_buffer = cport_id;
/* Find a free urb */
urb = next_free_urb(es1, gfp_mask);
if (!urb)
return ERR_PTR(-ENOMEM);
usb_fill_bulk_urb(urb, udev,
usb_sndbulkpipe(udev, es1->cport_out_endpoint),
transfer_buffer, transfer_buffer_size,
cport_out_callback, hd);
retval = usb_submit_urb(urb, gfp_mask);
if (retval) {
pr_err("error %d submitting URB\n", retval);
free_urb(es1, urb);
return ERR_PTR(retval);
}
return conceal_urb(urb);
}
/*
* The cookie value supplied is the value that buffer_send()
* returned to its caller. It identifies the buffer that should be
* canceled. This function must also handle (which is to say,
* ignore) a null cookie value.
*/
static void buffer_cancel(void *cookie)
{
/*
* We really should be defensive and track all outstanding
* (sent) buffers rather than trusting the cookie provided
* is valid. For the time being, this will do.
*/
if (cookie)
usb_kill_urb(reveal_urb(cookie));
}
static struct greybus_host_driver es1_driver = {
.hd_priv_size = sizeof(struct es1_ap_dev),
.buffer_send = buffer_send,
.buffer_cancel = buffer_cancel,
.submit_svc = submit_svc,
};
/* Common function to report consistent warnings based on URB status */
static int check_urb_status(struct urb *urb)
{
struct device *dev = &urb->dev->dev;
int status = urb->status;
switch (status) {
case 0:
return 0;
case -EOVERFLOW:
dev_err(dev, "%s: overflow actual length is %d\n",
__func__, urb->actual_length);
case -ECONNRESET:
case -ENOENT:
case -ESHUTDOWN:
case -EILSEQ:
case -EPROTO:
/* device is gone, stop sending */
return status;
}
dev_err(dev, "%s: unknown status %d\n", __func__, status);
return -EAGAIN;
}
static void ap_disconnect(struct usb_interface *interface)
{
struct es1_ap_dev *es1;
struct usb_device *udev;
int i;
es1 = usb_get_intfdata(interface);
if (!es1)
return;
/* Tear down everything! */
for (i = 0; i < NUM_CPORT_OUT_URB; ++i) {
struct urb *urb = es1->cport_out_urb[i];
if (!urb)
break;
usb_kill_urb(urb);
usb_free_urb(urb);
es1->cport_out_urb[i] = NULL;
es1->cport_out_urb_busy[i] = false; /* just to be anal */
}
for (i = 0; i < NUM_CPORT_IN_URB; ++i) {
struct urb *urb = es1->cport_in_urb[i];
if (!urb)
break;
usb_kill_urb(urb);
usb_free_urb(urb);
kfree(es1->cport_in_buffer[i]);
es1->cport_in_buffer[i] = NULL;
}
usb_kill_urb(es1->svc_urb);
usb_free_urb(es1->svc_urb);
es1->svc_urb = NULL;
kfree(es1->svc_buffer);
es1->svc_buffer = NULL;
usb_set_intfdata(interface, NULL);
udev = es1->usb_dev;
greybus_remove_hd(es1->hd);
usb_put_dev(udev);
}
/* Callback for when we get a SVC message */
static void svc_in_callback(struct urb *urb)
{
struct greybus_host_device *hd = urb->context;
struct device *dev = &urb->dev->dev;
int status = check_urb_status(urb);
int retval;
if (status) {
if ((status == -EAGAIN) || (status == -EPROTO))
goto exit;
dev_err(dev, "urb svc in error %d (dropped)\n", status);
return;
}
/* We have a message, create a new message structure, add it to the
* list, and wake up our thread that will process the messages.
*/
greybus_svc_in(hd, urb->transfer_buffer, urb->actual_length);
exit:
/* resubmit the urb to get more messages */
retval = usb_submit_urb(urb, GFP_ATOMIC);
if (retval)
dev_err(dev, "Can not submit urb for AP data: %d\n", retval);
}
static void cport_in_callback(struct urb *urb)
{
struct greybus_host_device *hd = urb->context;
struct device *dev = &urb->dev->dev;
int status = check_urb_status(urb);
int retval;
u16 cport_id;
u8 *data;
if (status) {
if ((status == -EAGAIN) || (status == -EPROTO))
goto exit;
dev_err(dev, "urb cport in error %d (dropped)\n", status);
return;
}
/* The size has to be at least one, for the cport id */
if (!urb->actual_length) {
dev_err(dev, "%s: no cport id in input buffer?\n", __func__);
goto exit;
}
/*
* Our CPort number is the first byte of the data stream,
* the rest of the stream is "real" data
*/
data = urb->transfer_buffer;
cport_id = (u16)data[0];
data = &data[1];
/* Pass this data to the greybus core */
greybus_data_rcvd(hd, cport_id, data, urb->actual_length - 1);
exit:
/* put our urb back in the request pool */
retval = usb_submit_urb(urb, GFP_ATOMIC);
if (retval)
dev_err(dev, "%s: error %d in submitting urb.\n",
__func__, retval);
}
static void cport_out_callback(struct urb *urb)
{
struct greybus_host_device *hd = urb->context;
struct es1_ap_dev *es1 = hd_to_es1(hd);
int status = check_urb_status(urb);
u8 *data = urb->transfer_buffer + 1;
/*
* Tell the submitter that the buffer send (attempt) is
* complete, and report the status. The submitter's buffer
* starts after the one-byte CPort id we inserted.
*/
data = urb->transfer_buffer + 1;
greybus_data_sent(hd, data, status);
free_urb(es1, urb);
/*
* Rest assured Greg, this craziness is getting fixed.
*
* Yes, you are right, we aren't telling anyone that the urb finished.
* "That's crazy! How does this all even work?" you might be saying.
* The "magic" is the idea that greybus works on the "operation" level,
* not the "send a buffer" level. All operations are "round-trip" with
* a response from the device that the operation finished, or it will
* time out. Because of that, we don't care that this urb finished, or
* failed, or did anything else, as higher levels of the protocol stack
* will handle completions and timeouts and the rest.
*
* This protocol is "needed" due to some hardware restrictions on the
* current generation of Unipro controllers. Think about it for a
* minute, this is a USB driver, talking to a Unipro bridge, impedance
* mismatch is huge, yet the Unipro controller are even more
* underpowered than this little USB controller. We rely on the round
* trip to keep stalls in the Unipro controllers from happening so that
* we can keep data flowing properly, no matter how slow it might be.
*
* Once again, a wonderful bus protocol cut down in its prime by a naive
* controller chip. We dream of the day we have a "real" HCD for
* Unipro. Until then, we suck it up and make the hardware work, as
* that's the job of the firmware and kernel.
* </rant>
*/
}
/*
* The ES1 USB Bridge device contains 4 endpoints
* 1 Control - usual USB stuff + AP -> SVC messages
* 1 Interrupt IN - SVC -> AP messages
* 1 Bulk IN - CPort data in
* 1 Bulk OUT - CPort data out
*/
static int ap_probe(struct usb_interface *interface,
const struct usb_device_id *id)
{
struct es1_ap_dev *es1;
struct greybus_host_device *hd;
struct usb_device *udev;
struct usb_host_interface *iface_desc;
struct usb_endpoint_descriptor *endpoint;
bool int_in_found = false;
bool bulk_in_found = false;
bool bulk_out_found = false;
int retval = -ENOMEM;
int i;
u8 svc_interval = 0;
udev = usb_get_dev(interface_to_usbdev(interface));
hd = greybus_create_hd(&es1_driver, &udev->dev);
if (!hd) {
usb_put_dev(udev);
return -ENOMEM;
}
/* Fill in the buffer allocation constraints */
hd_buffer_constraints(hd);
es1 = hd_to_es1(hd);
es1->hd = hd;
es1->usb_intf = interface;
es1->usb_dev = udev;
spin_lock_init(&es1->cport_out_urb_lock);
usb_set_intfdata(interface, es1);
/* Control endpoint is the pipe to talk to this AP, so save it off */
endpoint = &udev->ep0.desc;
es1->control_endpoint = endpoint->bEndpointAddress;
/* find all 3 of our endpoints */
iface_desc = interface->cur_altsetting;
for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
endpoint = &iface_desc->endpoint[i].desc;
if (usb_endpoint_is_int_in(endpoint)) {
es1->svc_endpoint = endpoint->bEndpointAddress;
svc_interval = endpoint->bInterval;
int_in_found = true;
} else if (usb_endpoint_is_bulk_in(endpoint)) {
es1->cport_in_endpoint = endpoint->bEndpointAddress;
bulk_in_found = true;
} else if (usb_endpoint_is_bulk_out(endpoint)) {
es1->cport_out_endpoint = endpoint->bEndpointAddress;
bulk_out_found = true;
} else {
dev_err(&udev->dev,
"Unknown endpoint type found, address %x\n",
endpoint->bEndpointAddress);
}
}
if ((int_in_found == false) ||
(bulk_in_found == false) ||
(bulk_out_found == false)) {
dev_err(&udev->dev, "Not enough endpoints found in device, aborting!\n");
goto error;
}
/* Create our buffer and URB to get SVC messages, and start it up */
es1->svc_buffer = kmalloc(ES1_SVC_MSG_SIZE, GFP_KERNEL);
if (!es1->svc_buffer)
goto error;
es1->svc_urb = usb_alloc_urb(0, GFP_KERNEL);
if (!es1->svc_urb)
goto error;
usb_fill_int_urb(es1->svc_urb, udev,
usb_rcvintpipe(udev, es1->svc_endpoint),
es1->svc_buffer, ES1_SVC_MSG_SIZE, svc_in_callback,
hd, svc_interval);
retval = usb_submit_urb(es1->svc_urb, GFP_KERNEL);
if (retval)
goto error;
/* Allocate buffers for our cport in messages and start them up */
for (i = 0; i < NUM_CPORT_IN_URB; ++i) {
struct urb *urb;
u8 *buffer;
urb = usb_alloc_urb(0, GFP_KERNEL);
if (!urb)
goto error;
buffer = kmalloc(ES1_GBUF_MSG_SIZE_MAX, GFP_KERNEL);
if (!buffer)
goto error;
usb_fill_bulk_urb(urb, udev,
usb_rcvbulkpipe(udev, es1->cport_in_endpoint),
buffer, ES1_GBUF_MSG_SIZE_MAX,
cport_in_callback, hd);
es1->cport_in_urb[i] = urb;
es1->cport_in_buffer[i] = buffer;
retval = usb_submit_urb(urb, GFP_KERNEL);
if (retval)
goto error;
}
/* Allocate urbs for our CPort OUT messages */
for (i = 0; i < NUM_CPORT_OUT_URB; ++i) {
struct urb *urb;
urb = usb_alloc_urb(0, GFP_KERNEL);
if (!urb)
goto error;
es1->cport_out_urb[i] = urb;
es1->cport_out_urb_busy[i] = false; /* just to be anal */
}
return 0;
error:
ap_disconnect(interface);
return retval;
}
static struct usb_driver es1_ap_driver = {
.name = "es1_ap_driver",
.probe = ap_probe,
.disconnect = ap_disconnect,
.id_table = id_table,
};
module_usb_driver(es1_ap_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Greg Kroah-Hartman <gregkh@linuxfoundation.org>");